Preparation And Adhesive Properties Of Soybean Oil Based Self-Healing Polymers Based On Multiple Hydrogen Bonds

Under the background of global climate and environmental crises caused by the depletion of fossil resources and excessive CO₂ emissions,the use of biomass raw materials with many advantages such as low-carbon,renewable and sustainable to replace petroleum-based materials can greatly reduce greenhouse gas emissions,improve the environment,protect ecology,and conform to the global consensus of low-carbon and sustainable development and the national strategy of“carbon peaking and carbon neutrality”.However,most bio-based polymers have shortcomings such as high production cost,poor strength,and easy crack damage during use,resulting in the inability of materials to be used for a long time,which greatly limits the promotion and application of bio-based polymer materials.In order to overcome this defect,the researchers explored biomass-based polymers with self-healing function,so that polymer materials can heal damage under certain conditions after damage,so that they can continue to be used normally,which is conducive to reducing resource consumption and improving the service life of materials.Among biomass resources,soybean oil has gradually become a research hotspot for bio-based polymers due to its advantages of high yield,low price and easy processing.In this paper,soybean oil-based self-healing polymer materials based on multiple hydrogen bonds were prepared by a series of chemical reactions using soybean oil as raw material,and its structure and properties were studied,and the application of soybean oil-based self-healing polymers in bonding and other fields was explored.This study is of great significance for the research and development of soybean oil-based self-healing polymer materials,and can provide a theoretical and experimental basis for the efficient utilization of soybean oil.The main research work is as follows:（1）Using soybean oil（SO）and vanilline（V）as raw materials,first reaction of soybean oil with ethanolamine to prepare N-hydroxyethyl fatty amide,and then N-hydroxyethyl fatty amide and vanillin were prepared by esterification reaction with methacrylic anhydride（MA）,respectively.Characterize the molecular structure of MASO and MAV by infrared and nuclear magnetism.The results showed that in the infrared spectrum of MASO,a new absorption peak of the ester group appeared at 1734 cm^-1,and a new absorption peak corresponding to the double bond and methyl group appeared at 5.27-6.11 and 1.88 ppm of the nuclear magnetic hydrogen spectrum,indicating the successful synthesis of MASO.In the infrared spectrum of MAV,new absorption peaks corresponding to C=C and ester bonds appeared at 1748 cm^-1 and1603 cm^-1,respectively,and new absorption peaks corresponding to C=C and methylene at5.80 and 2.00 ppm of nuclear magnetic hydrogen spectra,indicating the successful synthesis of MAV.（2）Using MASO and allyl urine（AU）as raw materials,self-healing polymer P（MASO-co-AU）based on multiple hydrogen bonding dynamic crosslinking network was prepared by ultraviolet light curing method.P（MASO-co-AU）shows excellent self-healing ability in both wet and dry environments,especially after self-healing by hot pressing,the mechanical property repair efficiency can reach 300%.In addition,P（MASO-co-AU）has excellent adhesion properties to various substrate surfaces,and the best bonding strength is achieved when MASO:AU is 9:1,and the dry shear strength of wood substrate and steel substrate is 1.17±0.04 MPa and 1.75±0.09 MPa,respectively.As a bio-based adhesive,it can be used as a self-healing patch in dry and wet environments,and can maintain an effective time of 12～24 h.In addition,the carbon nanotubes（CNT）and P（MASO-co-AU）/CNT composites were prepared by composite carbon nanotubes（CNT）and P（MASO-co-AU）/CNT composites,which exhibited conductivity in various environments and still showed good self-repair,and could carry 200 g load after repair.（3）A series of self-healing polymer P（MASO-co-AT）based on multiple hydrogen bonds were prepared by random copolymerization method using MASO and allyl thiourea（AT）as raw materials.By changing the ratio of MASO to AT,the performance of P（MASO-co-AT）can be adjusted.P（MASO-co-AT）can effectively adhere to various substrates,and maintain excellent bonding strength in different bonding environments,when MASO:AT is 9:1,the bonding strength is the best,the dry shear strength of wood substrate and steel substrate is 2.21MPa and 2.06 MPa,respectively,as a self-healing patch even in a humid environment can maintain 12～24 h effective time.In addition,the polymer showed good self-repair,and the mechanical properties and repair efficiency exceeded 80%.After adding carbon nanotube composites,the mechanical properties of P（MASO-co-AT）/CNT composites decreased by20%,but they still had self-healing properties,and also showed good electrical conductivity,ensuring that the circuit was connected at least 24 h in the circuit with a voltage of 19 V.（4）Using MASO,MAV and AU as raw materials,a self-healing polymer P（MASO-AU-MAV）based on Schiff base（dynamic imine bond）and multiple hydrogen bond was prepared by random copolymerization.P（MASO-AU-MAV）showed excellent self-healing performance under heat,organic solvents,1.80 W/cm² infrared radiation and 2450MHz microwave stimulation,and the repair efficiency was above 80%.P（MASO-AU-MAV）/Fe₃O₄ composite material is prepared by composite with nano-Fe₃O₄,which realizes non-contact welding at break,can withstand 100 g load after welding repair,and the repair efficiency is more than 60%.This study provides a promising strategy for the development of biomass resources and bio-based composites with good repairability.